SUMMARY This renewal study will examine how use of patient-facing digital health technologies impacts quality and resource use for patients with diabetes. Using a 13 year study period (2007-2019), we exploit the staggered implementation of mobile applications, web-based wellness programs, and patient-provider video-visits between 2008-2014, among a large population of over 200,000 patients with diabetes (ongoing or new diagnoses). The integrated delivery system setting provides comprehensive capture of diagnostic and treatment data (including medications, lab results and imaging) across all of a patient?s clinicians (primary care and specialists) in inpatient and outpatient settings, and make integrated data available to patients through the portal mobile applications. We were successful in our original study examining the impact of clinician-facing electronic health records (EHRs), finding associations with improved diabetes care quality (increases in guideline-recommended testing and treatment), and clinical outcomes (improved blood sugar and lipid control, reductions in emergency room visits and hospitalizations). This renewal proposal extends this line of inquiry to include novel patient-facing technologies. All of the technologies we will examine are well-integrated with patients? ongoing health care providers and broader clinical EHR, in contrast with the growing number of health applications available for patient download that are a data dead-end, leading to more fragmented care. The main proposed study predictor is patient technology use (mobile applications, web-based wellness programs, and patient-provider video-visits). In Aim 1, we will examine whether use of patient-facing technologies improves quality of care in patients with diabetes, specifically examining guideline-adherent prescription drug use and laboratory monitoring, drug adherence, and physiologic disease control (lab values) for diabetes and for any of four other comorbid chronic conditions (Asthma, CAD, CHF, and HTN). In Aim 2, we will examine resource use outcome measures including outpatient visits, emergency department visits, and non-elective hospitalizations. Using marginal structural models, we will test the hypotheses that patient technology use is associated with improved quality and lower in-person visit rates, while accounting for patient engagement, recent changes in health status, case-mix, cost-sharing for in-person visits, and patient demographic and socio-economic characteristics. The proposed study is likely to be the largest rigorous study of the impact of patient-facing technology use on health outcomes, including patient-provider video visit telehealth. By examining an early adopter of the technologies, and patients with diabetes who have complex clinical and self- management needs, this project has the potential to provide timely evidence to inform emerging telehealth and mhealth policies, technology adoption decisions, and real world use by clinicians and patients.